— Are blood clots normal during a period?

— Endometriosis can cause painful and heavy periods.

— Is It Normal for Period Blood to Come Out in Clumps?

People may worry if they notice clots in their menstrual blood, but this is perfectly normal and rarely cause for concern.

Menstrual clots are a mixture of blood cells, tissue from the lining of the uterus, and proteins in the blood that help regulate its flow.

Some medical conditions can cause large blood clots, often alongside heavy menstrual bleeding or period pains. People should see a doctor if they are concerned about their menstrual clots.

What does it mean to have clots in menstrual blood?

Blood clots are a natural part of menstruation.

It might be surprising to see a thick glob of menstrual blood, but, in most cases, blood clots are a natural part of menstruation.

It does not usually mean that there is a problem, but sometimes it can be a sign of a health condition.

Blood clots are a natural part of the body’s defense mechanism. The thick, jelly-like texture of a menstrual clot helps prevent too much blood from escaping.

This is the same clotting function that happens elsewhere in the body is an injury to the tissue, such as a cut or laceration.

Menstrual clots generally occur when the flow is heavy. They are more common during the first 2 days of menstruation, which is typically the heaviest part of a period.

Clots can be bright in color, or a darker, deeper red. More sizeable clots may look black. Menstrual blood begins to appear darker and more brown toward the end of each period as the blood is older and leaving the body less quickly.

When do clots happen?

Clots happen when the uterine lining sheds increased amounts of blood. When the blood pools in the uterus or vagina, it begins to coagulate, much like it would on an open skin wound.

The consistency of menstrual blood varies both throughout the period and from one period to another.

People may experience a heavy flow containing menstrual clots one month, and a lighter flow with no clots the next month.

This variation is natural, and changes may occur due to diet and lifestyle factors.

Causes of menstrual clots

During menstruation, the endometrial cells that line the uterus strip away and leave the body.

As this happens, the body releases proteins that cause the blood in the uterus to coagulate. This coagulation prevents the blood vessels in the uterine lining from continuing to bleed.

The blood that the body has already shed also contains these coagulation proteins.

When the flow is most substantial, the coagulation proteins within the blood may start to clump together, resulting in menstrual clots.

This generally occurs when menstrual blood pools in the uterus or vagina before leaving the body.

Possible health conditions

Although it is normal to have clots in the blood during menstruation, this symptom can sometimes signal a medical issue. It is advisable to seek medical advice if the clots:

are larger than a quarter in size

are very frequent

occur with an abnormally heavy flow that requires a person to change their pad or tampon at least every 1–2 hours

occur with significant pain

The following conditions may cause abnormal menstrual clots:

Uterine polyps or fibroids

A blockage in the uterus may stop it from contracting as it should, meaning that it cannot force the blood out as quickly as usual. The blood will leave the body more slowly so it will have more time to pool and form clumps.

The blockage can also cause a heavier flow, which results in more blood pooling.

Blockages may occur as a result of growths in the uterus. These include uterine polyps and fibroids, which are not cancerous but can cause other health issues without proper management.

Uterine polyps and fibroids consist of either endometrial or muscular tissue that grows in the uterine wall. They can cause symptoms such as:

persistent lower back pain

pain during sex, or dyspareunia

feeling bloated

fertility issues

irregular spotting

Endometriosis

Endometriosis is a condition that causes the tissues of the uterine lining to grow outside of the uterus.

This abnormality can lead to several symptoms, which may be worse around the time of menstruation.

When to see a doctor

People who are experiencing very heavy menstrual bleeding or have clots larger than a quarter in their menstrual blood should see a doctor, especially if they have any of the signs or symptoms of the conditions mentioned above.

What is a heavy flow?

A person with heavy menstruation may have to change their pad, tampon, or menstrual cup more than once every 2 hours for part of their period. They may also need two pads at a time and may miss out on everyday activities due to their menstrual flow.

Anemia

People with very heavy periods have a higher risk of iron-deficiency anemia.

Anemia occurs when there are fewer red blood cells in the body than usual. Low iron levels can cause this because the body needs iron to make new healthy blood cells.

Other symptoms of iron deficiency include:

general fatigue

weakness

shortness of breath

Anyone who is uncertain about their menstrual clots should see a doctor.

Diagnosis and treatment of abnormal menstrual clots

A diet that includes iron-rich foods may help with menstrual blood clots.

To diagnose the cause of abnormal menstrual clots, a doctor may ask about signs and symptoms, order blood or imaging tests, carry out a physical examination, or a combination of these.

Finding out the cause will allow a doctor to recommend the most appropriate course of treatment.

Doctors may advise taking an iron supplement if they believe that someone is losing too much blood or may be at risk of anemia.

They may also suggest some actions that people can take at home, such as:

staying hydrated with water

avoiding aspirin, which may make bleeding worse

eating a healthful diet that includes iron-rich foods

doing regular physical activity

Medication

Doctors may prescribe hormonal medications to help balance the hormones and control heavy bleeding.

They may suggest using or changing a birth control method. Intrauterine devices (IUDs) containing progestin may reduce blood flow, and some birth control pills may also help.

Doctors may recommend taking nonsteroidal anti-inflammatory drugs (NSAIDs) during the period to help reduce symptoms, such as cramping, pain, and discomfort. The NSAIDs may also help with excessive bleeding.

People who prefer not to use hormone treatments may wish to try medications that control blood clotting instead. It is best to speak to a doctor about this.

Outlook

Menstrual clots are normal and usually a symptom of heavy menstrual flow.

However, anyone who notices a pattern of heavy flow or heavy clotting alongside other symptoms should see a doctor.

There are a few different causes of abnormal menstruation. A doctor can help find effective ways to treat the underlying issues and control frequent or large menstrual clots.